Transcript Theory & Practice

Ecological Restoration (BIO 409)
Dr. McEwan
Restoration Theory and Practice
Concept review.
Keystone Species
Keystone...
Concept review.
Keystone species have a
disproportionately large influence on
ecosystem structure and function.
Remove the species, the whole
ecosystem can change
Management/Restoration of
keystone species (particularly
predators) is often an important goal
of restoration.
Concept review.
Umbrella species are those that have
habitat requirements such that managing for
that species will de facto protect a much
broader suite of species. This is also called
a “spillover effect” (see Box 5.1 in Falk et al)
Mussels are the classic umbrella species in
our part of the world. Require cold, clean,
streams…not a lot of those left
http://fw.ky.gov/pdf/t&ebook.pdf
A tiny fraction of federal funds goes to
species such as mussels, or plants or
insects, or obscure animals. Most funding
to charismatic megafauna
Concept review.
Flagship species are those that are
especially inspirational, thus stand as a
representative of a particular ecosystem.
These species may be ancillary from an
ecological perspective, but they draw
attention to the system.
Regional Processes Filter
1) Composition of the species pool and what is the
mechanism of species moving into local
ecosystems?
-lottery model = “more tickets better chance”
but still random.
-core & satellite = bimodal, many dominant
some rare.
2) Dispersal and colonization processes.
-priority effects
Local Environmental Filter
Restoration relies on creating environmental conditions sufficient to
maintain/perpetuate the species assembly desired in the restoration
target community.
-Abiotic conditions: light levels, soil pH, water availability, in wetlands
hydroperiod; in streams, things like depth and sinuosity. One of the first
goals in restoration is to create the appropriate environmental template.
-Disturbance regimes: fire, flooding, grazing and other perturbations are
critical to the maintenance of some ecosystems. These non-equilibrium
processes can reduce competition and create appropriate
environmental conditions for restoration success (eg, create exposed
soil for seed germination). Can also have a major influence on
ecosystem processes.
-Habitat complexity: In many cases, restoration seeks to restore some
degree of environmental/habitat complexity to systems that have been
simplified. Adding sinuosity to streams is an example.
Biotic Filter
Abiotic processes, mutualism, competition, etc., are important in
regulating ecological community structure and function. Restorationists
must understand (and often manipulate) these processes.
-Competition:
i) Resource competition.
ii) Top-down vs. Bottom-up processes.
iii) Invasive species have “changed the game” in many systems.
-Food-web/Trophic interactions: Need to understand how target species
may be interacting or depending upon other organisms. Will discuss
this later in detail (chapter 8)
-Mutualism: Grossly underappreciated. Could “make or break” a
restoration activity.
Questions at the end of chapter 5
1) “Commerce” to and from communities?
2) Role of hidden players?
3) Disturbance vs. biodiversity theory in
driving/explaining ecosystem function.
4) New theory for urban ecosystems?
5) Multiple-functions?